I tried both using a rigid body with 1m / s2 acceleration and also a program-defined body (without defining faces previously) and putting a movement defined by 1m / s2 acceleration. In either case the body moves for just over 1 sec and reports error code 2. The movement is noticeable. I was more successful in moving a submerged sphere, which moved longer and could see the wave generated by the movement, but it also stopped by an error after a while. I have been more fortunate in leaving my body still and accelerating the water around him with one face defined as inlet and other as outlet.